With the advances in the fractionalization of manufacturing processes of processors included in information processing apparatuses such as high performance computers (HPCs), servers, personal computers (PCs), and mobile phones, and the computation speed per processor has been improved. This involves desire to increase the capacity and band of a main memory.
Japanese Laid-open Patent Publication No. 2006-215799 and Japanese Laid-open Patent Publication No. 9-198300 discuss related art.